A series of event-=related functional magnetic resonance imaging (fMRI) studies are proposed to investigate the functional neuroanatomy of working memory, with special emphasis on inhibitory control as an executive function. This new technology, along with careful and precise manipulations of task parameters that are known to interfere with working memory performance will be used to accomplish several objectives that include: 1) identify regions of the prefrontal cortex (PFC) that are responsible for the protection of information in working memory from cortex (PFC) that are responsible for the protection of information in working memory from internal (i.e., stemming from mnemonic representations) and external (i.e., stemming from non-mnemonic, perceptual distraction) sources of interference; 2) characterize the material-specific (i.e., verbal, object, spatial) effects of proactive interference; and 3) characterize the differential effects of having distractors that are of the same or different material type as the information being maintained (e.g., verbal maintenance and verbal distraction vs. verbal maintenance and spatial distraction). The overall goal of this project is to precisely characterize the neural and cognitive processes mediated by the PFC that support the ability to suppress inappropriate or irrelevant information that can interfere with working memory.